diff --git a/include/git2/errors.h b/include/git2/errors.h
index 9dd42f0c4..63b6bc8ee 100644
--- a/include/git2/errors.h
+++ b/include/git2/errors.h
@@ -30,6 +30,7 @@ enum {
 	GIT_EORPHANEDHEAD = -9,
 	GIT_EUNMERGED = -10,
 	GIT_ENONFASTFORWARD = -11,
+	GIT_EINVALIDSPEC = -12,
 
 	GIT_PASSTHROUGH = -30,
 	GIT_ITEROVER = -31,